A composition comprising an oil of lubricating viscosity and a compound represented by formula (I) wherein: R.sup.1 and R.sup.2 are each independently a hydrocarbyl group containing from about 4 to about 18 carbon atoms; p and q are each independently 0 or an integer from 1 to 3, and the sum of p and q is 1, 2, 3, 4, 5, or 6. The composition is effective at swelling seals. ##STR00001##

A composition comprising an oil of lubricating viscosity and a compound represented by formula (I) wherein: R.sup.1 and R.sup.2 are each independently a hydrocarbyl group containing from about 4 to about 18 carbon atoms; p and q are each independently 0 or an integer from 1 to 3, and the sum of p and q is 1, 2, 3, 4, 5, or 6. The composition is effective at swelling seals.

##STR00001##

A method for preventing or reducing engine knock or pre-ignition in a high compression spark ignition engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition that contains (i) a lubricating oil base stock comprising at least one ester including at least one group selected from the group consisting of Formula (1), Formula (2), and Formula (3): ##STR00001##
The lubricating oils of this disclosure are useful as passenger vehicle engine oil (PVEO) products.

A method for preventing or reducing engine knock or pre-ignition in a high compression spark ignition engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition that contains (i) a lubricating oil base stock comprising at least one branched ester having at least about 15% of the total carbons in the form of methyl groups, and (ii) at least one ashless antiwear additive selected from a phosphorus-containing ashless antiwear additive, a sulfur-containing ashless antiwear additive, and a phosphorus/sulfur-containing ashless antiwear additive. A lubricating engine oil having a composition that contains (i) a lubricating oil base stock comprising at least one branched ester having at least about 15% of the total carbons in the form of methyl groups, and (ii) at least one ashless antiwear additive selected from a phosphorus-containing ashless antiwear additive, a sulfur-containing ashless antiwear additive, and a phosphorus/sulfur-containing ashless antiwear additive. The lubricating oils of this disclosure are useful as passenger vehicle engine oil (PVEO) products.

A method for preventing or reducing engine knock or pre-ignition in a high compression spark ignition engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition that contains (i) a lubricating oil base stock comprising at least one ester including at least one group selected from the group consisting of Formula (1), Formula (2), and Formula (3):

##STR00001##

The lubricating oils of this disclosure are useful as passenger vehicle engine oil (PVEO) products.